1. Field of the Invention
The present invention relates generally to switchgear for the field of electrical power distribution, and more particularly to an enclosure for pad-mounted installation of switchgear to provide separate access to and isolation between medium-voltage cable termination arrangements and the low voltage control, testing and viewing provisions.
2. Description of the Related Art
Switchgear are generally categorized by their installation location (e.g. grade or surface, sub-surface etc.), the configuration of components (e.g. loadbreak switches, fuses, interrupters, disconnects, sectionalizers, etc.), the cable connections (e.g. elbows, cable terminators), the accessibility of components and controls, the medium within the switchgear enclosure, for example air, vacuum, oil, gas (such as SF.sub.6), etc., and additional features such as fault indicators, voltage indicators, power operation, automatic fault interruption control, etc. Various enclosures for pad-mounted installations are known that provide security and access features for operation of the switchgear or components housed therein. For example, see U.S. Pat. Nos. 4,986,578, 4,489,966, and 3,572,062 for arrangements to secure access to pad-mounted gear.
While the enclosures of the prior art arrangements may be useful to provide certain useful operational features, the prior arrangements are rather limited regarding accessibility, ease of fabrication, and ease of operation for switchgear that is housed in a sealed tank and that includes arrays of low-voltage controls and viewing provisions of internal switch positions, and arrays of medium-voltage cable terminations. For example, the switchgear of U.S. Pat. No. 5,521,567 would be extremely useful for pad-mounted installations if suitable enclosures were available.